Portable electronic devices require user interfaces that enable users to easily access various services for the purpose of satisfying their various desires.
The portable electronic device needs user interfaces considering limited display areas because the limited display areas are needed for increasing portability. For example, if a portion of content that a user wants to see is displayed on the display unit of a portable electronic device, the portable electronic device provides a user interface that enables the user to scroll that content so that he/she may see another portion of the content that is not displayed.
When a touch screen is used, the portable electronic device may scroll content to respond to the touch information sensed through the touch screen. For example, if a drag operation on the touch screen (a touch input→a touch move→a touch release is sensed, the portable electronic device may scroll content based on a drag direction and a drag distance.
However, when there are a lot of areas that are not displayed on the display unit of the portable electronic device, there is inconvenience that a user of the portable electronic device needs to repetitively perform the same touch input for a scroll operation. For example, when a portion of E-book content that includes a plurality of pages is displayed on the display unit of the portable electronic device, there is inconvenience that a user of the portable electronic device needs to repetitively perform a drag operation (which might include a first touch input, then a second touch move, then a third touch release) to see areas that are not displayed.